We explore how we can use synthetically generated RGB-D training data from a near photo-realistic game engine to train modality-specific person detectors. We perform ablation studies on a challenging, real-world dataset which we recorded using a Kinect v2 RGB-D sensor in multiple warehouse environments. Through extensive use of domain randomization techniques, we synthesize a realistic and highly varied training set of challenging intralogistics scenarios as observed from a mobile robot, comprising persons in confined and cluttered indoor spaces. We then train the detector layers of a YOLOv3 model from scratch on our synthetic RGB and jet-encoded depth images. While for the RGB case, we still observe a domain gap of 6 points in mAP compared to a pretrained COCO model, results indicate that by exploiting simulation, an immense manual labeling effort needed to prepare large-scale datasets such as MS COCO might be unnecessary for the depth modality. We further find that filtering of highly occluded groundtruth boundin boxes during training, as well as modeling of time-of-flight sensor noise characteristics has a positive impact on model performance. We also provide an initial set of qualitative results on our real-world dataset.

An accurate understanding of the environment is key for a robot in order to execute tasks safe and efficiently. In the field of perception, after the introduction of deep learning, computer vision tasks have made big leaps, surpassing even the human inference capability. As a trade-off, big amounts of annotated data were required to train such algorithms. On its own, the collection of annotated dataset is a highly time consuming activity prone to human errors, setting a limit to the maximum achievable performance. In this sense, annotations (quality) and samples (quantity) bound the optimization of perception algorithms. One extra challenge encountered when training object detectors for robotics applications is that the sensor setup can be multi-modal, and vary significantly between robots. This work explores how to generate and use synthetic RGB-D training data from a near photo-realistic game engine to train modality-specific person detectors, and perform ablation studies on a challenging, real-world dataset recorded using a reference RGB-D sensor in different intralogistics environments. A virtual RGB-D camera was implemented, leveraging the underlying deferred rendering architecture. Multiple environments were tailored, exploring various data augmentation techniques and enabling the comparison between different types of synthetic data. Detection layers of a pre-trained object detector network have been trained from scratch for the RGB and depth modality, with the latter being transformed by applying a Jet-colormap. Compared to a pre-trained network, a domain gap of 5 mPA points was still present for RGB images. Meanwhile with synthetic (15k) and real (1.5k) depth images, it was already possible to train robust human detectors. Comparing simulation features against data preparation, filtering annotations had a major impact on performance than adopting an explicit time-of-flight sensor model.

Tackling climate change effects worldwide brings the interest of many donor countries with expertise to (co)develop solutions into beneficiary countries through international cooperation. The solutions proposed can be either too solution-driven, understood as a donor country selling its knowledge / products, or on the other hand, too locally problem-driven, which is desirable in theory, but facing practical limitations such as time or scale constraints when closing to outside influences. A methodology that tries to join both (apparently opposing) sides, with their advantages and disadvantages of problem and solution driven hasn’t been explored yet.For exploring how this can be done, in this research 2 case studies are analyzed: the Bangladesh Delta Plan 2100 (BDP2100), a nation-wide long term holistic plan on the Bangladeshi Delta, and a group of Coastal Water Management initiatives, a set of continuous efforts to adopt livelihoods to the dynamic situation in the coastal regions of Bangladesh. These cases are analyzed through interviews and desk research to determine to what extent are they problem and solution driven compared to proposed frameworks and pointing how can they be improved. From these analyses, a combined framework is proposed where problem and solution driven approaches are joined taking the best from each perspective. The result is meant to be a first guiding tool for decision-makers in donor and beneficiary countries that face the dilemma between taking local and foreign elements for developing solutions. Resumen Hacer frente a los efectos del cambio climático en todo el mundo atrae el interés de muchos países donantes con experiencia para (co) desarrollar soluciones en los países beneficiarios, a través de la cooperación internacional. Las soluciones propuestas pueden ser demasiado orientadas a la solución, entendidas como un país donante que vende sus conocimientos / productos o, por otro lado, demasiado localmente orientadas a los problemas, lo que es deseable en teoría, pero enfrentan limitaciones prácticas como limitaciones de tiempo o escala cuando se cierran a influencias externas. Aún no se ha explorado una metodología que intente unir a ambas partes (aparentemente opuestas), con las ventajas y desventajas de soluciones basadas en desarrollo netamente de problemas y desarrollo netamente de soluciones. Para explorar cómo se puede combinar esto, en esta investigación se analizan 2 casos de estudio: el Bangladesh Delta Plan 2100 (BDP2100), un plan holístico a largo plazo a nivel nacional en el delta de Bangladesh, y un grupo de iniciativas de gestión costera del agua, un conjunto de esfuerzos continuos para adoptar medios de vida a la situación dinámica en las regiones costeras de Bangladesh. Estos casos se analizan a través de entrevistas e investigaciones teóricas para determinar en qué medida están orientados a los problemas y soluciones en comparación con los marcos propuestos, y señalan cómo pueden mejorarse. A partir de estos análisis, se propone un marco combinado donde se unen los enfoques impulsados por problemas y soluciones, tomando lo mejor de cada perspectiva. El resultado pretende ser una primera herramienta de guía para los tomadores de decisiones en los países donantes y beneficiarios que enfrentan el dilema entre tomar elementos locales y extranjeros para desarrollar soluciones.

Abstract: Adequate initial bolt preload is necessary to ensure the strength and stiffness of bolted connections. In this study, an experimental torque control method was used to determine the relationship between tightening torque and preload of nine Extended Hollo-Bolt (EHB) blind bolted connections to Concrete-Filled Steel Hollow Sections (CFSHS). In order to obtain the EHB nut factors, which allow to calculate the level of preload for any value of applied torque, torque versus preload curves were drawn based on the experimental results and curve fitting method was carried out. Bolt preload relaxation was also recorded for a period of 7 days while concrete hardening occurred. Additionally, a detailed 3D Finite Element (FE) model of the tightening stage of the EHB was established. The experimental and numerical results show that the nut factor for the EHB is higher than that of standard bolts and bolt relaxation is not affected by the concrete presence during the hardening stage. Adequate friction coefficients were proposed as well as an equation for calculating the residual preload of the EHB. Resumen: Es necesaria una precarga inicial adecuada del perno para garantizar la resistencia y rigidez de las conexiones atornilladas. En este estudio, se utilizó un método experimental de control de torque para determinar la relación entre el torque de apriete y la precarga de nueve conexiones empernadas ciegas Extended Hollo-Bolt (EHB) a secciones huecas de acero rellenas de concreto (CFSHS). Para obtener los factores de tuerca EHB, que permiten calcular el nivel de precarga para cualquier valor de torque aplicado, se dibujaron curvas de torque versus precarga con base en los resultados experimentales y se llevó a cabo el método de ajuste de curvas. También se registró la relajación de la precarga de los pernos durante un período de 7 días mientras se producía el endurecimiento del hormigón. Además, se estableció un modelo 3D detallado de elementos finitos (FE) de la etapa de apriete del EHB. Los resultados experimentales y numéricos muestran que el factor de tuerca para el EHB es mayor que el de los pernos estándar y la relajación del perno no se ve afectada por la presencia del concreto durante la etapa de endurecimiento. Se propusieron coeficientes de fricción adecuados así como una ecuación para calcular la precarga residual del EHB.

Abstract: This study investigates the combustion characteristics of blends of bituminous coal (BC) with two by products of the coffee industry, spent coffee ground (SCG) and coffee husk (CH), at 10, 30, and 50 wt% using a thermogravimetric analyzer (TGA). For comparison purposes, blends of BC and wood pellets (WP) at the same mass ratios were also investigated. The thermal behavior and fuel interactions in the blends during combustion were characterized by the ignition index (Di), combustion index (S), and potential synergistic effects. The interactions between the materials in the blends led to an enhancement of up to 93.5% and 128.5% in Di, and 175.2% and 96.35% in S of the bituminous coal when blended at 50 wt% with SCG and CH, respectively. Furthermore, clear synergistic effects were observed with the combustion of BC-SCG blends, whereas the combustion of BC-CH blends did not show any appreciable synergistic effects.

Abstract: The aim of this research was to investigate the combustion behaviour of coal and biomass blends using a pilot-scale bubbling fluidised bed reactor. The blends were prepared with a traditionally used biomass fuel (i.e. wood) and selected rich in alkali-metals biomass fuels (i.e. wheat straw and spent coffee grounds (SCG)) to investigate the potential of SCG as a fuel and the effect of ilmenite on agglomeration tendency when used as an additive and alternative bed material. To elucidate the interaction between the fuels in the blends and the effect of ash composition, thermogravimetric and ash fusibility studies were performed looking at both the parent fuels and blends. Initially, thermogravimetric studies focused on understanding the thermal decomposition of coal blended with by-products (spent coffee ground (SCG), and coffee husk (CH)) of coffee crop. Blends with wood were included for comparison purpose. The blends were prepared by blending coal with biomass at 10, 30 and 50 wt%. The experiments were performed under inert and oxidising conditions to elucidate the thermal behaviour and fuel interactions. The results showed that the inclusion of either spent coffee grounds or coffee husk in coal combustion can enhance the combustion performance. Indeed, the blends with spent coffee grounds were found to be more reactive than those with coffee husk and with similar characteristics to the blends with wood. It was attributed to the existence of synergistic effects. These results offer compelling evidence of the potential of by-products from the coffee crop, especially spent coffee grounds for energetic applications. The study of ash fusibility characteristics investigated the ash fusibility temperatures under oxidising conditions of coal ash blended with ash from spent coffee grounds. Blends with wheat straw ash were included for comparison purpose. Particular attention was paid to the blending ratio effect on ash fusibility temperatures. The results showed that SCG is an interesting fuel in co-processing due to the low ash content and high ash fusibility temperatures when blended with coal. The high ash fusibility temperatures of the blends were attributed to the high content of CaO, MgO, and P2O5 in SCG with negligible content of SiO2 and Cl, complementing the high content of Al2O3 and Fe2O3 in coal. Evidence from this study suggests that the high ash fusion temperatures in the blends of coal with spent coffee grounds can reduce the common operational issues related to biomass ash such as agglomeration. This can also provide confidence for large scale thermochemical conversion systems fuelled by such kind of coal and biomass blends to be able to maintain long-term stable operation. The final part of this research focused on co-combustion experiments in a pilot-scale BFB aiming to investigate the potential of SCG as a fuel, and ilmenite as an additive and alternative bed material. For comparison purpose blends of coal with wheat straw and wood pellets were also combusted in the same BFB reactor under similar combustion conditions. Similarly, kaolin and bauxite, and silica sand were compared to ilmenite when used as an additive and alternative bed material, respectively. The inclusion of biomass in coal combustion showed marked differences in the temperature profiles, gas emissions, and combustion performance. The results showed that coal and SCG blends can be combusted for energy applications with improved combustion efficiency compared to wheat straw and wood commercial pellets. Nevertheless, high N content in SCG represents a challenge in terms of NOx emissions that should be addressed.

Abstract: Dissolved air flotation (DAF) is considered better than conventional gravity settling (CGS) for the treatment of algal-laden waters, and ballasted sedimentation (BS), a high-rate separation process, is now often used instead of CGS. Our initial literature search did not identify DAF-BS comparisons for the removal of algae and cyanobacteria from algal laden waters. The objective of this benchscale study was to compare DAF with BS and CGS for the treatment of water from a eutrophic waterway (Bay of Quinte, ON). The study was performed mid-summer when there was substantial algal growth. The optimized BS jar tests had 3% lower average turbidity removal than the DAF jar tests, however BS required 33% more coagulant, as well as 0.25 mg/L anionic polymer and microsand additions. The removal of cyanobacteria and algae (quantified using chlorophyll-a and c-phycocyanin concentrations) by DAF and BS were very similar, and they were superior to that achieved by CGS. The DOC removals and the disinfection by-products formation potential (DBPFP) of DAF and BS treated water were also similar. Based on the chlorophyll-a and c-phycocyanin removals, both BS and DAF performed better than CGS and can be considered suitable for the treatment of algal/cyanobacteria laden waters.

Abstract: The standard IEC 61400-1, v.4.0 proposes at appendix J a method to determine the probability of extreme winds, based on the simulation of artificial cyclones and the theory of gradient wind. This method considers marginal statistical distributions for 5 main descriptors of cyclones (pressure depth, radius of maximum wind speed, translation speed, angle to the point of reference and mini-mum distance), a “modified orthogonal decomposition” to generate artificial cyclones and its own formulas to determine surface wind, cumulative probabilities and annual maximum surface wind. This research pursued to implement and to validate the standard at North West Pacific. Due to the difficulty and highly empirical elements of IEC 61400-1, v.4.0, it was required to modify it and include in the model other inputs such as well known statistical distributions after testing them, Nataf trans-formation (ERANataf) to generate artificial cyclones and empirical cumulative distribution functions to determine the probability of annual maximum surface wind. For the verification and validation, the results of 9 locations distributed in South Korea, Japan, HongKong and Taiwan were compared with the database of the Joint Typhoon Warning Center and theRSMC-Tokyo. The implementation of this research underestimated surface wind in all the locations.Simultaneously, the greatest contribution of input variables to sensitivity was more frequent from super index B of Holland. It would be desirable to continue validating this standard (that is presumed to have a global application), to understand the challenges of its theory during the computation of surface wind from gradient wind and to overcome the issues of its implementation.

Abstract: Fluid storage capacity measurements of core plugs in the laboratory consider pore volume as a function of effective stress. The latter is equal to applied confining pressure – n × applied pore pressure. However, the results are often reported as a function of difference in the applied pressures, because the effective stress coefficient (n) is an unknown. This creates confusion during the interpretation of laboratory data and leads to added uncertainties in the analysis of the storage capacity of the samples under in-situ conditions. In this paper, we present a new laboratory method that allows simultaneous prediction of the sample pore volume, the coefficient of isothermal pore compressibility, and the effective stress coefficient. These quantities are necessary to predict the fluid storage as a function of effective stress. The method requires two stages of gas (helium) uptake by the sample under confining pressure and pore pressure and measures pressure-volumedata. Confining pressure is always kept larger than the equilibrium pore pressure, but their values at each stage are changed arbitrarily. The analysis is simple and includes simultaneous solutions of two algebraic equations including the measured pressurevolumedata. The model is validated by taking the reference pore volume near zero stress. The reference volume predicted matches with that measured independently using the standard helium porosimeter. For sandstone, shale, and carbonate samples, the estimated pore compressibility is, on average, 10−6 psi−1. The effective stress coefficient is higher than unity and is a linear function of the ratio of the applied pressure values. We present a new graphical method that predicts the Biot coefficient (α) of the rock sample, a fundamental quantity used during the strain calculations that indicates the tendency of the rock to deform volumetrically. A new fundamental rule is found between the applied pressure difference and the effective stress: σe/α = pc − pp. Interestingly, the predicted Biot coefficient values for the shale samples show values between 0.46 and 1.0. This indicates that features of the shale sample, such as mineral variability, fine-scale lamination, and fissility, come into play during the fluid storage measurements. Resumen: Las mediciones de capacidad de almacenamiento de fluidos en tapones de núcleo en el laboratorio consideran el volumen poroso como una función del esfuerzo efectiva. Esta última, es igual a la presión de confinamiento aplicada - n × presión de poro aplicada. Sin embargo, los resultados a menudo se reportan como función de la diferencia en las presiones aplicadas, porque el coeficiente de esfuerzo efectivo (n) es desconocido. Esto crea confusión durante la interpretación de los datos de laboratorio y genera incertidumbres adicionales en el análisis de la capacidad de almacenamiento de las muestras en condiciones in situ. Resumen: En este artículo, presentamos un nuevo método de laboratorio que permite la estimación simultánea del volumen poroso de la muestra, el coeficiente de compresibilidad de poro isotérmico y el coeficiente de esfuerzo efectivo. Estas cantidades son necesarias para predecir el almacenamiento de fluido en función del esfuerzo efectivo. El método requiere dos etapas de absorción de gas (helio) por la muestra bajo presión de confinamiento y presión de poro y mide los datos de presión-volumen. La presión de confinamiento siempre se mantiene mayor que la presión de poro de equilibrio, pero sus valores en cada etapa pueden cambiar arbitrariamente. El análisis es simple e incluye soluciones simultáneas de dos ecuaciones algebraicas, incluidos los datos de presión-volumen medidos. El modelo se valida tomando el volumen de poro de referencia cerca de la tensión cero. El volumen de referencia estimado coincide con el medido de forma independiente utilizando un porosímetro de helio estándar. Para las muestras de arenisca, lutita y carbonato, la compresibilidad de poro estimada es, en promedio, 10−6 psi − 1. El coeficiente de esfuerzo efectivo es mayor a la unidad y es una función lineal de la relación de los valores de presión aplicados. Presentamos un nuevo método gráfico que predice el coeficiente de Biot (α) de la muestra de roca, una cantidad fundamental utilizada durante los cálculos de deformación que indica la tendencia de la roca a deformarse volumétricamente. Se encuentra una nueva relación fundamental entre la diferencia de presión aplicada y el esfuerzo efectivo: σe / α = pc - pp. Curiosamente, los valores del coeficiente de Biot estimado para las muestras de lutitas muestran valores entre 0,46 y 1,0. Esto indica que las características de la muestra de lutita, como la variabilidad mineral, la laminación a escala fina y la fisibilidad, entran en juego durante las mediciones de almacenamiento de fluidos.

Abstract: Using low-cost gas sensors for air quality monitoring promises cost e ective and convenient measurement systems. Nevertheless, the results obtained have a questionable quality due to di erent factors that can a ect sensor performance. The most discussed ones are relative humidity and air temperature. This investigation aimed to assess the behavior of B4-series low-cost gas sensors from Alphasense for measuring CO, NO, NO2, and O3 for di erent levels of relative humidity and temperature. These low-cost gas sensors were tested for six relative humidity levels from 10% to 85% with increasing steps of 15% and four temperature levels of 10 C, 25 C, 35 C, and 45 C against reference instruments in the laboratory. The e ect of these parameters on low-cost gas sensors was quantified in laboratory from which a correction algorithm was calculated, which was then applied to the field data. The applied algorithm improved the data quality of the low-cost gas sensors in most of the cases. Additionally, a low-cost dryer was assessed to reduce the influence of these factors on the low-cost gas sensors, which also proved to be suitable to enhance the data quality.